This research proposal is designed to enable participation in (continued participation in) the Primary Breast Cancer Therapy Group-NSABP. The overall specific aims of the NSABP are to improve disease-free survival in patients with primary operable breast and colorectal cancers. (See the NSABP Headquarters grant application for protocol rationale and overall scientific achievements to date.) The Jewish General Hospital has been an NSABP member since September 1971 an is currently following 626 patients previously randomized on long-term adjuvant protocols. We expect to maintain (increase) patient accrual at 65+ per year. The entry of these patients into NSABP protocols will enable a more rapid and effective evaluation of current therapeutic regiments and will provide information for the design of future studies. The Jewish General Hospital is a key institutional member playing an important role in group activities. a) one of the largest accruers - consistently increasing. b) consistently the highest quality Data (4 consecutive awards) c) key role in protocol design and strategic input d) administrative and committee role (Executive Committee, Surgical Monitoring Committee etc.)